Magnetic tape data storage device



Feb. 16, 1965 J- RABl-NOW 3,169,686

MAGNETIC TAPE DATA STORAGE DEVICE Filed Dec. 14, 1962 IN VENT-OR. Jacob Rab/now @QXW A TTORNE YS United States Patent 3,169,686 MAGNETIC TAPE DATA STORAGE DEVIE Jacob Rahinow, Bethesda, Md., assignor, by mesne assignments, to Control Data Corporation, Minneapolis, Minn, a corporation of Minnesota Filed Dec. 14, 1962, Ser. No. 244,625

13 Claims. (Cl. 226-26) This invention relates to magnetic tape devices and particularly to magnetic tape units of the type used in data processing systems.

Magnetic tape units are Widely used as storage media, buffers, etc. in many kinds of data processing systems involving computers, calculators, character reading machines, and others. The more successful units have two storage reels for the tape, a pair of dancers or tensioning device engaging loops of the tape, and a pair of capstan drivers between which the magnetic head or heads are located to be operable with the tape. An arrangement such as this is shown, for instance, in the Goldberg et al. Patent No. 2,867,791. That patent also describes some of the demands on the tape unit, which are made by a computer or the like, and some of the difi iculties that are encountered. For instance, the ideal tape unit would be capable of instantly stopping on a single bit recorded on the tape, and instantly starting at the full, design speed. Theoretically these ideals cannot be achieved in a direct manner. One reason is that instantly starting a tape from a rest position to design speed would mean that the instantaneous acceleration of the tape is enormous. A capstan driver tape transport is probably the most satisfactory device to move tape, but when used to approach the ideal instant stop, start and reversal, the tape breaks, it throws loops and otherwise behaves unsatisfactorily. Furthermore, when the tape is payed out from one reel and wound on the other, the effective diameters of the tape on the reels continually changes and this introduces other problems which are known in the art.

Possibly, to reduce these or other difiiculties with the reel-capstan drive type of magnetic tape a class of machines using a magazine-type tape accumulator has been developed. US. Patent No. 2,979,244 exemplifies this kind of machine. One of the main difiiculties with the magazine-accumulator type of tape transport is that the stant starting is not achieved, it is more easily and closely approached than with the usual reel-type magnetic tape unit.

One of the major objections to the magazine ac-' cumulator tape unit is its comparatively small capacity for tape-length storage. There is a limit on the height of the tape buffer compartment because the tape folds at the bottom of the stack crush if the stack becomes too heavy (tall).

An object of my invention is to improve the above dis cussed type of magnetic tape machine by horizontally enlarging the tape compartment and providing means to move the tape stack into the compartment enlargement.

Another object of the invention is to provide means for controlling the tape-stack moving-means in response to a condition of the stack which directly effects the preservation or lack of preservation of the smoothly curved folds of the stack. Thus, I have means to weigh the stack of tape and when the weight reaches a predetermined maximum, my control means either initiate or modify the actuation of a conveyer to move the stack of tape into (or from) the compartment extension.

In one form of my invention the lower part of the vertical compartment of the magnetic tape unit is horizontally extended and a flexible belt conveyer is provided at the bottom thereof. A set of weighing scales is at the bottom of the vertical portion of the compartment and the weighing scales are so arranged that when a suflicient predetermined weight is sensed by the scales, an electrical signal is provided for modifying the operation of the conveyer, for example, by starting the conveyer. Alterna-tively, the conveyer can be continuously operated and the electrical signal used asa servo accelerate (or decelerate) the conveyer.

accumulator must have a comparatively smallcapacity to storetape-lerigth. My invention (a) overcomes this difficulty in the magazine accumulator type'of magnetic unit designed by Pike, and (b) provides a new kind of tape unit using the'magazine concept of having loose storage of tape (instead or reels,)fwhich is discussed later.

Magazine accumulatortransports have one ,(or more),

vertical compartment of awidth somewhat. greater thanthe width of the magneticjtaper, Instead of winding the tape on reels as" is now done inmany'typesof conventional tape machines, the compartment supports a stack of double-back,snioothly'curvedfolds arranged in serpntine manner from which and; to.. which' the magnetic tape is payed outand fed during the magneticread,

write, and/or erasemodes of operation. The preferred means to drive the tape are the sameas inrjeel type mamagnetic 'head or heads and with the capstans. Briefly, the advantage of the magazine accumulator machine is this: when the tape is ac chines, i.e., a pair ofcapstans on oppositefsidesof the pinch. rollers cooperating P celerated, the only restrainingiforceto. the acceleration of the tape is derived from the ing), the same benefit'is obtainedbecause, again, there mass of ashort length 9f 1 tape, i.e., the length of'tape'from'the top of the previously mentioned. stack through the capstan driver as-. semblies. Therela're no dancers nor'tap'e" feels. to contend with, In the stopping mode (with or without reverstion tape is fedl'into comingtape which forms newfolds. transport operates in the opposite direction the conveyer vided a closed-loop tape where the tape can be enormously long in comparison to currently used magnetic belts of the closed-loop type. This is accomplished with a single compartment provided with a balance beam weighing scalev associated with a conveyer control at the bottom of the tape unit. The arrangement is such that the folds of tapeforma copious tape supply on the conveyer, a'ndpthe scalespcausethe conveyer to operate in either direction to vr'nov'e the tape folds left or right dependingon the following requirements. :When the conventional tape transport movesthe tape in one direc one end of the supply of folds and is withdrawn from the other. The scales detect thisfand 1 cause the conveyer'tofoperate in one direction to help feed from theoutgoing folds and make room for the in- When the tape operates correspondingly for the same reason. Accordingly, another object of my invention is to provide a*-new kind of tape unit with ample tape'capacity and with favorable stop, start and reversal characteristics made possible by very low inertia of the small quart; tity of tape between the tape transport and aloos'e. supplyobjects and feature'sof importance' -will become apparent in following the description of the illustrated 1. forms of the inventionfwhich are given 'by wayof exa ml ly V .1 t 3 5....51

Other The ends of the tape are fixed,

I similar folding" V h I Since'the vertical heightofthe staclr is limited by the tresistanoe of the tape "to beooming shalply lci eased; my p I I invention rnalte's use of the horizontalextensifonsljz of the 1 p compartments in the following'manner: apaii of endless I beltconveyors' ttl and d2 are located atf the'ibottorn f compartments 20.22am their extensions." 'COI1Yeyer's4ii an 42 are made of belts entrained overya pairiofi idler pulleys 44 (FI GURE 1) at one end oflthe icompartment ei;tensions, and drivennollers th; 47 at the opposite end; 7 Both pairs of rollers aremounted on spindles 48 "connected FIGURE 1 is an elevational view of a magnetic tape machine constructed in-accordance'with my invention.

FIGURE 2 is an enlarged sectional view taken on line Z 2 of FIGURE 1. l

FIGURE 3 is a sectional view taken on line 3 1: oi

- FIGURE 2. V FIGURE 4-is a fragmentary sectional view taken on the line l4 of FIGURE'I.

FIGURE '5 is a fragmentary vertical sectional view showing another embodiment of my invention.

'Magnetic tapemachineltl (FXGURES 1-4) has a housing provided with a vertical partand a'horizontally extending partlZ at the lower side thereof, 'Tle housing' isconstructed of front and rear walls 14 and 16 (FIGURE 4) and a vertical partition 18. which divides the housing into parallel compartments '26 and 22. The

end, top and bottom walls of the housing and its extension are suitably connected to the-front and rear walls. The'upperfpart of thehousing contains conventional i tape transpont mechanisms 23 represented by oapstans 24 and .26 with their associated pinch rollers 28 and 3t 7 The. capstans are driven by conventional drive motors, and the pinch rollers 28 and 30 are actuated by conventional means which respond to'oommand signals emanating thorn an external machine or from the tape unit by actuation of switches. Magnetic head 32 is located between" the caps-tans and as is known in the art, tone or more heads can be used. A tape pressure pad 34 is attached to the.

' frame of machine it) and retainshhe tape against head 32. The capstans and pinch rollers are horizontally offset a from the other oapstan-roller combination. tioularly, as'a vertical group of smoothly curved folds are fiormed in the compartment 2d below the capstan driver, they will be conveyed (to the lllgl'lllfiS'ShOlYll in FlGURE V.

1) to occupy the lateral extension '12 of the tape compartmer t 20, and at the same time the folds in compartment 7 tical boahse-the height of the stack of folds is app-roxh' matelypnoportional to the'length of tape passing the magnetic head, theexpense fvor' -irnplementation is considera ably greater than myillustrated arrangement, As show-11' in FIGURE. 1, weighing scales 54 have a pan -56 beneath the'upper flight of conveyer 42 directly below the vertical part or the hou-5mg; Thus, the scales sense the weight and amount of tape as. Switch 58 is aemated'by the movement of a Weightresponsive partlof the scales, e.g;," pan 56, and switch 58 isa part of control cincuit 6% for motor 52. 'As mentioned before, motor 52 is reversible, and when energized in one of its two directions, i-t aotuates both conveyers but wsiniulta'neonsly'in opposite directions.

switch 64 which is manually or computer'aoperated. Switch 30.

slight distance so that an intermediate porti-onof the mag netic tape -36 is fed or withdrawn directly vertically from iooni partment Zttpor 22.. The ends of the tape are fiastened to the machine frame by clamp 37 behind tape-deflector 39 (FIGURE 1).

As discussed before, the space between Walls 14, 16 and the compartment-subdividing partition'lt} provides clearance for the width 0f the tape (FIGURE 4) to freely move in the compartments, but the clearance, is insufii-cient for a tape told 38 to twist or for one fold'to move vertiicallyalongside of another. Thus. when tape is fed into ously, other equivale-nticircuits (e.g.; a DC. motor and a reversing switoh to replace motor'SZ and switch 53) can" Circuit 69 has a power sourced; and ,a main control oiis connected in series with the movable contactor of switch 58." Thefixe'd'oontacts ofswitch 5% are connected with the forward and reverse windings of motor 52. Obvibe used. The operation of the circuit is apparent in FIGURES :when pan 56 senses little or no tape the pan moves up to its normal (no load) position causing switch 58 to close via its upper contact and the motor, causing motor 5 2 to operate in one direction, When'pan 5'6; senses a icompartrnent, it moves to the bottom thereof and as additional tape continues to feed therein, the tape flexes along the axis of least resistance (tnansversely a'cnoss the tape) and dorms the smoothly curved'folds 38 (FIGURE.

apredetermined load (by adj-Listing scales 54 or the con-' tacts ofswitch 58 switch 5811s closed via its lower-con tact causingthe motor to operate inthe opposite direction. When the pan senses )3 load between the 'tw-oextremes a switch 58-rerruains topentshiown). Obviously, I qanrinter- 1). The tape doubles back upon itself and the fold-form ing procedure continues building up a stack Fofdoubled back, smoothly-curved folds ofdifierent lengths. Due to normal tape-feeding operation, when the tape is being fed into com partment 2t) another portion of the tape is with drawn from oompartment 'When thetape is driven in the opposite direetion by the actuated pinohmoller and capstan of the tape transport,- the tape is withdnawn from f compartment 29 and fed intov tape oonmparmient with with wallsfll-and to? The conveyersare'actu-atedhy' a reversiblemotor 52 (FIGURES l3.) eoupled withjrolle'rs V i .45, '47 though tasnitable transmission drives ro ller I 146m tone direotionat thesiarne time that roller 47 is driven I f the opposite direction. Belts (reg, Ofrings).g49; Eden gagingTpu-lleys on the m otorshaft and attached to sellers tablefwhen one ofthe. beltsislcno-ssed; smu

ndf @2} are automatically operated inpppo awa h ma ia safi we e i ake room tortheinoorn g tap pose variable resistors in the oirouit tio obtainspeed and/or variable servo control-of motor'52.

Summarizing, the pnactieal lirnit ontho arn'onntof tape thatrcan be used in a magazineaccumulator-type tape transpolt is' established byjthe height at which the tape 7 folds begin to'c'reasel The form of my invention shown in p FIGURE "I greatly-enlarges the capacity for time storage by providing conveyors at the bottom or "m n e cornp'ar tments jand sensing th weigl'it'iof tape (on one (or both,

if .desited) ofi them; The tape weight'corres'ponds' to'ithe' tensions. liowe 7' v onveyers move foldslelit andfright (FIGURE '11 f ing' and feeding tape in the respectrve cjonipartments as it moved in the 'iisu'al wayby-the -tape transpoitQZS;

.. arouses show-s another-mm. frhyz maehine is? avherethe'hou ingwalls defineia'sin The tape capstan drivers, magnate headland tensioning device 'Jare theisarn'e as. in 1. The" I N 7 between ma .ichines gltiland Mia, rare that the yveighi-ngalefS E-a is :a Y

' ba me b m i he ane fifi i a os d-locp, ierid 0 1 9 ":veyerdza is, P V l V I '.come.apkproximatelycentered-bet eentheends;of the con i veyerJIistructunally irnachinevltla hasthe oapstan drivers 7 7 main diiferenoes, "apart 'fnom simplification,

erated in a thatlll6ff0ld5238tlb? near the left and right end walls, conveyer 4 20; is at the botto'rn of the 'machin I More par- 1 thestack of tape-folds; and a rate theoonveyersasaforea acilitate withdrawcompartment Etta.

hasfitsipan fioa'beneathjand meningit s ow {surface ance bean which pivots about transverse spindle 61. Thus, the tilting of pan 5611 indicates that more tape is being supported on one side or the other of spindle 61. For instance, with tape folds as shown in FIGURE 5 the left part of the pan 55a Will move down to close switch 58a in a manner to cause the motor-operated conveyer to move the tape folds to the right. When the folds move to about the center of the compartment, switch 58a will open by the lifting of the adjacent end of pan 56a. If the tape transport moves the tape in a manner that it begins to pile up on the right side of the conveyer 42a,

switch 58a will close through its upper contact to move the tape folds toward the center of compartment a. Thus, motor control circuit 664 is identical to circuit 60.

. Since only one conveyer 42a is involved, only one belt 491: (instead of crossed-'belts, FIGURE 3) and a pair of pulleys are required to couple the motor 52:: to conveyer 42a.

Since the weight of the tape is sensed through (by deflection of) conveyer belts in the two illustrated forms of my invention, the pans of the scales are in light contact therewith. The belts of the conveyers are preferably quite flexible such as woven cloth. Although small oscillations I of the pans of the scales will provide no diflieulty, I have shown dashpot 70 (FIGURE 5) attached to pan 56a and to the fname of the machine to solve any potential oscillation problem. If desired, a dashpot can be similarly used in FIGURE -1.

It is understood that various additional changes, modiaications and the like may be made without departing from the pnotection of the following claims.

I claim:

1. Ina magnetic tape machineprovided with a vertical compartment, a magnetic head at the upper part of the compartment, and forward and rearward drive means for the tape, said; compartment having walls which are so spaced as to require the supply. of tapein the compartment to form a 'vertical stack of doubled back smoothly curved folds in serpentine manner as the tape is fed into the compartment during operation of said drive means, the improvement comprising a substantially horizontal extension of said vertical compartment at the lower part thereof to enlarge the capacity for tapestorage, and means for moving the lower part of the vertical stack of smoothly curved folds into said horizontal compartment extension to thereby prevent the stack from exceeding a height in said vertical compartment which is, greatenough to cause the bottom folds to be crushed. 2 In a magnetic tape machine provided with a vertical compar'tment,' a magnetic head at the upper part of the compartment, means for driving said tape past said head in a selected forward or reverse direction, and said compartment having walls which are so spaced as to require the supply of tape in the compartment to form a vertical stack ofdoubled back smoothlycurved folds as the tape is fed into the compartment during operation of said 3. A magnetic tape unit comprising a housing having a vertical partition defining a pair of adjacent compartments, the width of'the compartments being slightly in excess of the width of the magnetic tape, a magnetic head,'drive meansto move said tape selectively in a forward or reverse direction past said head, conveyer means i said compartments for movinga supply of said tape in one compartment in a first direction and for moving a supply of the tape in the other compartment in a second direction depending on the direction of operation of said drive means so that when said tape is accelerated it is withdrawn from the'supply so that'substantially the only resistance to tape movement at initial starting is derived from the weight of a comparatively small length of the tape'froni the drive means to the supply from which the tape is drawn. v

4. The subject matter of claim 3 and means responsive to the weight of a portion of the tape for controlling the actuation of said conveyer means.

-5. In a magnetic tape machine, tape transport means to move the tape in a selected forward or reverse direction, a housing in which to store a quantity of tape from which tape is drawn and into which tape is fed in response to actuation, of said tape transport means, tape weight responsive means for moving said quantity of tape to a predetermined position within said housing, said Weight responsivemeans including a weighing scale, a tapesupporting conveyor disposed in said housing and operatively associated with'said scale,and conveyor operating means responsive to the actuation of said weighing scale.

6. Ina magnetic tape machine, tape transport means to move the tape in a selected forward or reverse direction, a housing in which to store ,a quantity of tape from which tape is drawn and into which tape is fed as a result of actuation of the tape transport means, tape weight responsive means to move said quantity of tape to a, predetermined position within said housing, said weight responsive means including a. weighing scale, a tape supporting conveyor operatively associated with said scale, conveyor operating'means responsive to the actuation of said Weighing scale, and said conveyor operating means having means to reverse the direction of motion of said conveying means.

7. In a magnetic tape machine, tape transport means to move the tape in a selected forward or reverse direction, a housing in which to store a quantity of tape from which tape is drawn and into which tape is fed in response .to actuation of said tape transport means, tape Weight responsive means for moving said quantity of tape to a predetermined position within said housing, said housing l having separate compartments in which said quantity of tape is stored in stacks of smoothfolds, and said tape quantity moving meansincluding separate conveyors at i the bottom of said compartments.

which tape is drawn and into which tape is fed as a' result of actuation of said tape transport means, said" 8. In a magnetic tape machine, tape transport means to move the tape in a selected forward or reverse direc-,

tion, a housing in which to store a quantity of tape from housing having separate compartments in which said quantity of tape is stored in stacks-of smooth folds, tape weight responsive means for moving said quantity of tape .to predetermined positions within said compartments, said tape quantity moving means including separate conveyors at the bottom'of said compartments, means to actuate means responsive to the weight of tape in said vertical. compartment for efiecting the operation of said moving 1 means;

said two directions.

said conveyors inunison but in opposite directions, and

means to reverse the operation of said conveyors.

9. In a machine forlhandling flexible tape, tape drive means to selectively move the tape in forward and reverse directions, an accumulator compartment for a buffer porportion, means for selectively operating said conveyor in one of two directions to correspondingly move the tape buffer portion Within the compartment and means responsive to said weighing means for actuating said conveyor operating means to move the conveyor in one of 10. Ina machine for handling magnetic tape and having a magnetic head structure, drive means to move part encased of the tape past said head in selected forward or reverse directions; a tape accumulator compartmentcontaining abufier portion of said tape arranged as .apluralityof loops to which tape isfed-and from which tape is. drawn 7 .by said drivenieans, weighing means to weigh the butter portio n' of the tape'in a part of said compartmcnt, and

means responsive to said Weighingmeans to relocate the tape buffer portion ,in said compartment to prevent the tape from excessively accumulating in a compartment.

oria reverse direction. j g V a 12.:Tl1e rnachine of claim ll wherein said weighing means include weighiug scaleaiand meansiiucluding a 1 -13; In a machine for handling magnetic tape and new ing a .rnagnetic head structure-tape transport means to drive thetape pastsaid'head structure selectively/in a for- War dot reverse direction, a compartmented housing con;

I t'aining abuffer portion of theirnagntictapesaid tape transport rneans drawing tape from a first end of said j butter portion and feeding tape into a'second end ofrsaid buffer portion; when the transport means drives said tape part of the AM L i L EeOL M N am? ERWARD A. saoKAgE mmer'. a

in the forwaid'directioni and said transport means vvithdrawing the tape from said second end of said buffer portion and feeding tape into said first end o fi said bufier portion when said transport means drives said tape in the reverse directionsoithatthe buffer portion of the tape accumulates in said compartmentedhousing at difierent positions depending-on the direction oi operatio njof said tape transport means, means to prevent excessive accurnuiation'of tape at either of saidibufferportion ends includ-f i 1 ing a conveyor in said compartment'ed housing, Weighing means to Weigh therbufier portioninsaid housing, and means including an electric circuit operativelyassociated with said weighing means for actuating said conveying ;means to move the tape" to a new position within said. housing which prevents excessive -tape accumulation at one jend'of said tapebur tej'rport-ion control; circuit responsive to the actuationot saidweigh-V v ting-means to-confrol'said motor drive means.

:Reference s-(Iited by the Examiner V UNITED STATES PATENTS Examiner. f

; 2/631 Altern1an -rzzsggsx; 

1. IN A MAGNETIC TAPE MACHINE PROVIDED WITH A VERTICAL COMPARTMENT, A MAGNETIC HEAD AT THE UPPER PART OF THE COMPARTMENT, AND FORWARD AND REARWARD DRIVE MEANS FOR THE TAPE, SAID COMPARTMENT HAVING WALLS WHICH ARE SO SPACED AS TO REQUIRE THE SUPPLY OF TAPE IN THE COMPARTMENT OT FORM A VERTICAL STACK OF DOUBLED BACK SMOOTHLY CURVED FOLDS IN SERPENTINE MANNER AS THE TAPE IS FED INTO THE COMPARTMENT DURING OPERATION OF SAID DRIVE MEANS, THE IMPROVEMENT COMPRISING A SUBSTANTIALLY HORIZONTAL EXTENSION OF SAID VERTICAL COMPARTMENT AT THE LOWER PART THEREOF TO ENLARGE THE CAPACITY FOR TAPE STORAGE, AND MEANS FOR MOVING THE LOWER PART OF THE VERTICAL STACK OF SMOOTHLY CURVED FOLDS INTO SAID HORIZONTAL COMPARTMENT EXTENSION TO THEREBY PREVENT THE STACK FROM EXCEEDING A HEIGHT IN SAID VERTICAL COMPARTMENT WHICH IS GREAT ENOUGH TO CAUSE THE BOTTOM FOLDS TO BE CRUSHED. 